Our experience with them was at least one major (longer than an hour) outages PER MONTH and many of those times they were black holing our routes in their network which was the most damaging aspect. The outages were one thing but when our routes still somehow managed to get advertised in their network (even though our BGP session was down) that really created issues. I have heard from some nearby folks who still have service that it's gotten better, but we are also in the "regional offering" when it comes to IP Transit and have sold connections to many former Cogent customers who were fed up and left. I have found with Cogent that you will get a LOT of varying opinions on them - there are several other players (at least in our market) that are priced very similar now and have a better history behind them..... The specific de-peering issues never effected us much due to enough diversity in our upstreams and a fair amount of direct/public peering... Thanks, Paul -----Original Message----- From: Justin Shore [mailto:justin@justinshore.com] Sent: Thursday, June 11, 2009 9:47 AM To: NANOG Subject: Cogent input I'm in search of some information about Cogent, it's past, present and future. I've heard bits and pieces about Cogent's past over the years but by no means have I actively been keeping up. I'm aware of some (regular?) depeering issues. The NANOG archives have given me some additional insight into that (recurring?) problem. The reasoning behind the depeering events is a bit fuzzy though. I would be interested in people's opinion on whether or not they should be consider for upstream service based on this particular issue. Are there any reasonable mitigation measures available to Cogent downstreams if (when?) Cogent were to be depeered again? My understanding is that at least on previous depeering occasion, the depeering partner simply null-routed all prefixes being received via Cogent, creating a blackhole essentially. I also recall reading that this meant that prefixes being advertised and received by the depeering partner from other peers would still end up in the blackhole. The only solution I would see to this problem would be to shut down the BGP session with Cogent and rely on a 2nd upstream. Are there any other possible steps for mitigation in a depeering event? I also know that their bandwidth is extremely cheap. This of course creates an issue for technical folks when trying to justify other upstream options that cost significantly more but also don't have a damaging history of getting depeered. Does Cogent still have an issue with depeering? Are there any reasonable mitigation measures or should a downstream customer do any thing in particular to ready themselves for a depeering event? Does their low cost outweigh the risks? What are the specific risks? Thanks Justin ---------------------------------------------------------------------------- "The information transmitted is intended only for the person or entity to which it is addressed and contains confidential and/or privileged material. If you received this in error, please contact the sender immediately and then destroy this transmission, including all attachments, without copying, distributing or disclosing same. Thank you."